1. Field of the Invention
The present invention relates to a packet data switching system.
2. Description of the Related Art
The conventional packet data switching system is typically comprised of a plurality of transfer control units that send and receive packets to be transferred between packet terminals, a call processing unit and a packet handling unit. All the above units are interconnected via a standard bus, a common bus or the like.
The conventional packet data switching system is however not suitable for coping with a heavy load of packet calls. To solve the above problem, a multiprocessor system such that each processor is connected to a data ring bus has been proposed, and thereby a large amount of data traffic can be dealt with.
As will be clarified hereinafter, the packet data switching system having the data ring bus is mainly comprised of a plurality of transfer control units that send and receive packet data to be transferred between packet terminals, a packet call processing unit and a data ring bus, to which the above transfer control units and packet call processing unit are connected.
In the above packet data switching system, along with a further increase in the data traffic between the packet terminals, a heavy load is applied to the packet call processing unit as well as the data ring bus. To cope with the above hereby load, preparation of a large capacity packet call processing unit and a large capacity data ring bus are required. For example, the packet call processing unit should be realized by a extremely high speed processor in the form of a multiprocessor. Further, employment of optical communication for the data ring bus is required. This apparently is not advantageous in constructing an economical packet data switching system.